In recent years, there has been a rapid proliferation of mobile phones. In some cases, a single person owns a plurality of mobile phones. Further, mobile phones are not only carried by persons. That is, a chip having a communication function is also attached to a pet, or a communication function is installed in a machine apparatus or the like, to carry out communication with the pet or the machine apparatus. Further, a service of attaching a chip or the like having a communication function to an item to be delivered, to thereby monitor the current location of the item, is also provided. In general, a forwarding agent gathers items to be delivered to a collection point or the like, and delivers each item from the collection point to a delivery destination. In such a case, a great number of items are collected at the collection point. Further, since the items can be stacked, the number of chips per unit area largely increases.